Specifications

CY7C65620
CY7C65630
Document Number: 38-08037 Rev. AB Page 28 of 32
Errata
This section describes the errata for the EZ-USB HX2LP™ Low-Power USB 2.0 Hub Controller Family, CY7C65620/30. Details include
errata trigger conditions, scope of impact, available workaround, and silicon revision applicability. Contact your local Cypress Sales
Representative if you have questions.
Part Numbers Affected
HX2LP Qualification Status
Product status: Production
HX2LP Errata Summary
1. Non-periodic and Isochronous OUT transfers in the same microframe
■Description
With the operating in High-Speed mode with a Full-Speed device connected to a downstream port, Sometimes, an Isochronous
OUT packet gets corrupted on the downstream port.
■Implication
The main cause of this phenomenon is in the way the hub's Transaction Translator downstream handler state machine schedules
transactions if non-periodic (Control or Bulk) transactions are found in the non-periodic buffer while an Isochronous OUT transac-
tion is active on the port. If the downstream handler state machine sees an Isochronous OUT packet in the Transaction translation
buffer and if it is scheduled in the same micro-frame by the host then it will skip the Isochronous OUT transaction and resume a
non-periodic transaction.
■Workaround
The workaround for this issue is for the host controller to avoid scheduling non-periodic traffic such that it will run while an
Isochronous OUT transaction is active. Non-periodic traffic can be scheduled to run in the micro-frame before the Isochronous
OUT transaction begins, or after the Isochronous OUT transaction completes.
■Status
No plan to fix currently - recommend using workaround.
2. Last data not received in multi-microframe Isochronous IN transfers
■Description
With the hub operating in High-Speed mode with a Full-Speed device connected to a downstream port, Sometimes a multi-micro-
frame Isochronous IN transaction resulted in the last two Complete Split transactions that should have returned data but instead
returned NYET handshakes.
■Implication
The main cause of this phenomenon is in the hub's Transaction Translator logic which tracks data stored in the periodic transaction
buffer. If the Full-Speed transaction completes before the Complete-Split token is received from the host, there is a chance that
buffer will be over-written if the requested Isochronous IN payload is greater than 440 bytes (USB 2.0 specification on buffer size).
■Workaround
The workaround for this issue is for the host controller to avoid scheduling the Complete Split token for the microframe where the
Full-Speed packet ends too late in the frame. The TT is guaranteed to work correctly if the Complete Split is received in the first
quarter of the microframe.
■Status
No plan to fix currently - recommend using workaround.
Part Number Device Characteristics
CY7C65620 All Packages
CY7C65630 All Packages